Supporters of Lebanon’s parliament speaker, Nabih Berri, blocked several roads with burning tyres across Beirut on Monday to protest leaked comments by Foreign Minister Gibran Bassil in which he called Berri a “thug”.

Berri’s Amal movement demanded an apology from the foreign minister, who is the son-in-law of President Michel Aoun and the head of the Free Patriotic Movement (FPM), the country's main Christian party. Both FPM and Amal are close allies of Hezbollah, the country’s most powerful group.

Gunfire was heard as Berri supporters gathered in a protest near offices of FPM in Jdeideh, a Christian neighbourhood east of Beirut, drawing soldiers to the area to prevent further trouble, security sources said.

Aoun has aligned himself with Hezbollah after returning to Lebanon from exile in France in 2005. The group's support played a major role in his election to the presidency in 2016 but the president’s relations with Hezbollah's Shia partner, Amal, remain shaky.

The crisis has spiralled since December when Aoun signed a decree promoting dozens of army officers without the signature of Shia Finance Minister Ali Hassan Khalil, one of Berri's closest aides.

Berri has said that by moving to promote pro-Aoun officers, the president has exceeded his powers at the expense of other sects.

On Sunday evening, Al Jadeed TV broadcast a video of Bassil from an election rally, where he accused Berri of deepening sectarian divisions and preventing Shia expatriates from attending events organised by the foreign minister during a visit to West Africa.

“This is a thug, not a speaker of the parliament,” Bassil said.

His comments were met with fury by Berri’s camp.

The crisis cast doubt on alliances being forged in the country's May parliamentary elections, the first since 2009.

The feud puts Hezbollah in an uneasy position between two vital allies.

Berri is an old civil war foe of Hezbollah, but his support helps in keeping Lebanon’s Shia community united behind the Iran-backed organisation. Meanwhile, Aoun represents a Christian partner that helps Hezbollah deflect accusations of sectarianism and extremism.

On Tuesday, Hezbollah appeared to back Berri in a statement, strongly rebuking Bassil for using language that “creates additional crises”. However, the group called for resolving the issue with “wisdom and responsibility”.

Aoun and Berri cooperated closely to help resolve the crisis caused by Prime Minister Saad Hariri's unexpected resignation in November. Lebanese officials say Saudi Arabia forced him to step down and held him against his will before French intervention led to his return.

Hariri said he was working on an initiative to end the Aoun-Berri standoff.

"The country is not in need of escalation or crisis," he said after talks with Aoun.